Why is N-well, P-well and power continuity required ?

[Gayathri Jeyaram]

Why are N-well, P-well and power continuity required ?

Hi,

Filler cells are added for n well, pwell and metal 1 continuity. Why should n well p well be continuous ? I understand that Metal 1 should be continuous for min density reasons and EM reasons.

What exactly is power continuity ?

Thanks in advance. :-D

 

[jbeniston]

Two reasons. Without continuity, the design rules would probably mean you would need to space things further apart. Also, the wells need to be tied to VDD/VSS. If they're continuous, you need less well ties.